Saliva management system with continuous flow through oral device

ABSTRACT

Systems for maintaining a vacuum in a patient&#39;s oral cavity comprises an oral device, a vacuum control system, and an assembly including first and second tubes for connecting the vacuum control system to the oral device. The oral device has an internal plenum, and a vacuum is drawn in the plenum by a vacuum pump connected by a first tube of the tubular assembly. The vacuum is maintained by an air source which is connected to the plenum by the second tube of the tubular assembly. By maintaining a constant circulating air bleed through the oral device and the connecting tubes, saliva may be removed from the system and collected in a saliva trap located before the vacuum pump.

CROSS-REFERENCE

This application is a divisional application of U.S. patent applicationSer. No. 14/624,088, filed Feb. 17, 2015, which is a divisionalapplication of U.S. patent application Ser. No. 13/023,763, filed Feb.9, 2011, which is incorporated herein by reference in its entirety, andto which applications we claim priority under 35 U.S.C. §121.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical devices and methods.In particular, the present invention relates to a system, device andmethod for managing saliva accumulation in an oral device that may beheld in the mouth of a patient to reduce the incidence of obstructivesleep apnea or snoring or for other purposes.

Obstructive sleep apnea (OSA) is a serious medical condition resultingfrom a temporary airway blockage which occurs as a patient sleeps. Theairway blockage usually occurs between the soft palate and/or the backof the tongue and the pharynx. As the patient breathes, the reduced areain the upper airway can cause snoring, and more seriously, OSA.

Sleep disruption caused by OSA can result in severe daytime sleepiness,chronic fatigue, headaches, depression, accidents, injuries, and ofparticular concern, OSA can reduce the amount of oxygen entering thelungs causing hypoxia. Hypoxia, in turn, can lead to pulmonaryhypertension, heart disease, and stroke.

Numerous invasive and less invasive treatments have been proposed forOSA. Of particular interest to the present invention, “continuouspositive airway pressure” (CPAP) delivers a continuous stream ofpressurized air directly to the person's upper airway. The positivepressure maintains potency of the airway and inhibits the collapseassociated with OSA. Although generally effective, CPAP suffers from anumber of drawbacks that have led to a high level of non-compliance. Thepatient must wear a bulky facial mask which can be uncomfortable, andthe system generates noise that can make falling asleep difficult. CPAPis also difficult to use because the mask requires careful fitting toavoid air leaks and facial discomfort and because the mask can easily bedislodged during sleep. Moreover, a number of unpleasant side effects,such as sore throats, dry throat and eyes, headaches, and skin rashesfrom the mask frequently occur. These problems have resulted in a highlevel of non-compliance with CPAP therapy.

As an improvement over CPAP, it has been proposed to apply a negativepressure to the patient's oral cavity. For example, devices have beenproposed which apply a vacuum at the forward end of the patient's mouth,typically at or just behind the lips, to pull the tongue forward inorder to lift the rear portion of the tongue away from the back of theairway. See, for example, U.S. Patent Publication Nos. 2007/0277818,2005/0166928 and 2005/0166929. As an improvement over these devices, ithas more recently been proposed to apply a negative pressure in regionor space above the tongue which in turn draws the soft palate away fromthe pharynx to draw the rear portion of the tongue away from the pharynxas well. See, commonly owned U.S. Patent Publication Nos. 2009/0120446and 2009/0120447.

With all such oral devices, saliva can accumulate in the vacuum linesand vacuum pump connected to the oral device. While it is proposed incommonly owned U.S. Patent Publication No. 2009/0123886 to collectsaliva from the vacuum lines using a liquid trap in the connecting linebetween the oral device and the pump, the saliva can still collect inthe connecting line and result in an unpredictable additional pressuredrop between the pump and the oral device. To help clear the connectingline, it is further proposed to provide a positive pressure pump tointroduce air to the oral cavity or to connect an air bleed line to theremote end of the vacuum line to allow a continuous air circulation.Even these measures, however, have not been entirely effective inremoving saliva from the system to eliminate blockages and unpredictablepressure drops. In particular, saliva can still accumulate in the oraldevice itself which can increase the actual pressure drop in ways thatare difficult to predict and address.

For these reasons, it would be desirable to provide alternative andimproved methods and apparatus for drawing a vacuum in a patient's oralcavity for treating obstructive sleep apnea and other purposes. Themethods and devices should be effective both in clearing saliva from thevacuum connecting line and in keeping the oral device free ofaccumulated saliva. The methods and systems should be simple andinexpensive to implement and add little or no complexity to the controlsystem At least some of these objectives will be met by the inventionsdescribed below.

2. Description of the Background Art

Commonly owned U.S. Patent Publication Nos. 2009/0120446; 2009/0120447;and 2009/0123886, have been described above. Oral and external devicesfor treating sleep apnea and snoring are described in U.S. PatentPublication Nos. US2005/166929; US2005/166928; US2008/0188947;US2007/0277818; US2008/0216843; and US2008/0210244; and in U.S. Pat.Nos. 7,182,082; 7,073,506; 7,073,505; 6,955,172; 6,877,513; 6,494,209;5,957,133; 5,465,734; 4,676,240; 4,304,227; 4,169,473; and 3,132,647;and in Cartwright and Samelson “The effects of a non-surgical treatmentfor obstructive sleep apnea: the tongue retaining device;” Journal ofthe American Medical Association 248 (1982).

SUMMARY OF THE INVENTION

The present invention provides systems, apparatus, and methods forinhibiting saliva accumulation in oral devices and systems which draw avacuum in a patient's oral cavity for treating obstructive sleep apnea(OSA) or for other purposes. The present invention provides for acontinuous air bleed circulation through all parts of the system wheresaliva might accumulate, particularly including the oral device andconnecting line(s) between the oral device and a vacuum pump andoptionally other system components. While other gases could be bledthrough the device, as a practical matter air will almost always beused.

The continuous air bleed circulation can be provided by making certainmodifications to the systems described in the commonly-owned publishedpatent applications above. First, the oral device is provided with avacuum plenum having an inlet and an outlet, as well as vacuum port(s)which are disposed to draw vacuum in the patient's oral cavity. A vacuumpump is connected to the plenum outlet of the oral device, and an airsource is coupled to the plenum inlet of the oral device. The vacuumpump is operated to draw a vacuum in the vacuum plenum while a small,controlled air bleed (typically in the range from 60 ml/min to 120ml/min) results from the air entering the plenum from the air source.This continuous air bleed circulation will occur even when the vacuumports in the vacuum plenum are receiving no air from the oral cavity. Inprior devices, when the vacuum ports were blocked, the saliva couldremain stagnant within the oral device and/or the connecting lines thuscompromising operation of the system.

The plenum within the oral device may have any one of a variety of flowpatterns. Most commonly, the plenum will extend from an inlet located atan anterior end of the device, through a first bite structure or leg ofthe device, across a cross-member at a posterior end of the device, andreturn through a second bite structure or leg of the device to theoutlet. In other configurations, however, the plenum within the oraldevice need not be continuous. For example, the plenum could extend fromthe inlet up through the first bite structure or leg and terminate at abypass outlet near a posterior end of the device. A second segment ofthe plenum, typically isolated from the first plenum segment, would havethe vacuum ports and provide a return path to the device outlet,typically through the second bite structure or leg. The desiredcontinuous air bleed circulation would thus pass through patient's oralcavity, where the air bleed would exit into the oral cavity through thebypass port and return into the second segment of the plenum through thevacuum port(s) on the posterior end of the device. In still anotherembodiment, plenum inlet and outlet segments can be formed in a singlebite structure or leg of the device by providing a dividing wall in aninterior luminal passage of the bite structure or leg. Thus, air canenter an inlet side of the plenum through the device inlet, flow to thevacuum port(s) on the posterior side of the device, and return to theoutlet through an isolated passage formed on the other side of thedividing wall. A variety of other structures may also be possible solong as those structures provide for the continuous bleed of air throughall air passages of the oral device including those within the regionadjacent to the vacuum port(s) on the posterior end of the device.

In a first aspect of the present invention, a system comprises an oraldevice and a vacuum control system. The oral device is positionable in apatient's oral cavity (i.e., an interior portion of the mouth) and has avacuum plenum with an outlet, an inlet, and one or more vacuum ports,typically located between the outlet and the inlet. The vacuum controlsystem includes a vacuum pump, an air source and optionally a salivatrap or other removal mechanism. The vacuum control system is connectedto the oral device by first and second tubes, where the tubes may beseparate or integrated into a common connector assembly. The first tubeconnects the inlet of the oral device to the air source of the vacuumcontrol system and the second tube connects the outlet of the oraldevice to the vacuum pump. The saliva trap, if present, is typicallydisposed between the outlet of the oral device and the vacuum pump ofthe vacuum control system, although it could be located after the pump.The “trap” could be any removal mechanism such as a separator, anevaporator, or any other component which removes, evaporates, orcollects the saliva.

The oral device of the system will usually comprise a base adapted to beheld between a patient's upper and lower teeth, where the base has ananterior end, a posterior end, and a cross-member extending across theposterior end of the device. The plenum usually extends around the baseand the vacuum ports are typically disposed on the cross-member whilethe plenum inlet and plenum outlet are disposed on an anterior end ofthe device. Optionally, for the treatment of OSA, the cross-member maybe adapted to engage and depress an engagement region of the tongue toallow a tongue region anterior to the cross-member to rise relative to aposterior region of the tongue, as described in more detail in thecommonly-owned publications cited above.

At least the vacuum pump, the air source, and the saliva trap of thevacuum control system will usually be contained or enclosed within acommon enclosure, typically a tabletop box. Optionally the system mayinclude sensors, such as pressure or flow sensors, to monitor thepressure or flow of the air bleed into the device and the pressureand/or flow of air being drawn from the device by the vacuum pump.Conveniently, such sensors may also be provided within the commonenclosure. Such pressure and/or flow sensors allow the system operationto be monitored and can alert the user should the pressures and/or flowsbe operating outside of their expected ranges. For example, a differencebetween the air bleed pressure going into the oral device and the vacuumpressure being drawn out of the oral device by the vacuum pump couldsignal a blockage or other malfunction within the oral device.

In a second aspect, the present invention provides an oral devicecomprising a base adapted to be held between a patient's upper teeth andlower teeth. The base has an anterior end, a posterior end, and across-member extending across the posterior end. A plenum extends withinthe base from an inlet on the anterior end, through the cross-member,and to an outlet on the anterior end. The inlet and the outlet areconnected by the plenum so that air entering the inlet flows through thecross-member before exiting the outlet. The oral device will furtherinclude at least one vacuum port, typically a plurality of vacuum portsformed in a wall of the cross-member in order to draw vacuum within thepatient's oral cavity when the oral device is held therein.

The base of the oral device will typically include left and right bitestructures, where the cross-member is disposed between the bitestructures at their respective posterior ends. The cross-member of thedevice will typically be spaced inferiorly of (below) the hard palatewhen the base is held between the patient's teeth. The cross-member isthus able to provide a clear region free from structure between thecross-member and the hard palate and extending to the patient's softpalate. The at least one vacuum port is typically disposed on a superior(upper) surface of the cross-member, and the device may further comprisea lip seal coupled to the base and/or the vacuum tubes to inhibit airfrom entering the oral cavity through the mouth while the vacuum isbeing applied. In the exemplary embodiments, the cross-member comprisesan arcuate rear edge and a curved superior surface. While the left andright bite structures and cross-member have been described separately,in some embodiments they will be formed as a single integrated structureas shown in the drawings.

In a third aspect, the present invention provides a method for drawing avacuum in a patient's oral cavity. The method comprises placing an oraldevice in the patient's oral cavity, where the device has an inlet, anoutlet, a plenum there between, and at least one vacuum port in aposterior region of the plenum. A vacuum is drawn on the plenum outletof the oral device while the device is in the patient's oral cavity inorder to establish an air flow into the plenum inlet, through the plenumand out from the outlet. The air flow into the inlet is typicallycontrolled or restricted to maintain a controlled vacuum in the plenum,where at least one of (1) drawing the vacuum and (2) restricting orcontrolling the air flow into the inlet to maintain a vacuum in theplenum in the range from 20 mmHg to 75 mmHg. In this way, saliva andmoist air which are drawn into the plenum from the patient's oral cavitymay be trapped or otherwise removed, typically using a moisture trap,filter or evaporator, after the air is withdrawn from the outlet of theoral device.

Restricting or controlling the air flow will typically comprise placinga fixed orifice before the device inlet. In the simplest cases, theorifice could be within the inlet itself, but having the inlet open withthe orifice risks the inlet getting blocked while the patient sleeps,either from debris or from the patient turning to block the inletorifice in the pillow or other bedding. Usually, it is preferable thatthe fixed orifice be disposed within the common enclosure of the controlsystem where it can be protected, thus minimizing the chance ofaccidental blockage. Alternatively, the air inlet flow and/or pressurecould be controlled using a pump or other active system.

The vacuum is typically controlled by controlling the vacuum pumpconnected to the device outlet. Moisture is trapped (separated orevaporated from the air flow) in a moisture (saliva) trap or similarstructure placed in a flow path downstream of the plenum outlet.Optionally, pressure or flow rate may be measured between the plenuminlet and the plenum outlet. Proper operation of the system can then bemonitored by comparing the measured inlet flow/pressure and the outletflow/pressure to confirm that they are within expected ranges.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a system constructed in accordance with theprinciples of the present invention in use by a patient.

FIG. 2 is a schematic illustration of an oral device in combination witha vacuum control system in accordance with the principles of the presentinvention.

FIG. 3 is a perspective view of an oral device useful in the systems ofthe present invention.

FIG. 4 is a partial cross-sectional view of the oral device of FIG. 3.

FIG. 5 is a schematic illustration of an alternative embodiment of theoral device of the present invention, said embodiment having a bypassport for passing the air bleed stream through the patient's oral cavity.

FIG. 6 is a schematic illustration of a further alternative embodimentof the oral device of the present invention showing air bleed inlet andoutlet paths through a single bite structure or leg of the device.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 1, a system 10 constructed in accordance with theprinciples of the present invention includes an oral device 12 (shown inbroken line in the oral cavity of a patient P), a control enclosure 14which is suitable for placement on the top of the table T, and aconnector line assembly usually including first and second tubularconnectors 18 and 20, better illustrated in FIG. 2-6.

Referring now to FIG. 2, the oral device 12 includes an internal plenum22 which extends from an inlet 24 to an outlet 26. The plenum 22 istypically integrally formed within the oral device 12, usually beingformed as part of a molding process. Alternatively, the plenum 22 couldbe formed separately and attached to a separate body of the device. Inaddition to the inlet 24 and outlet 26, the oral device will include oneor more vacuum ports 27, where the inlet s are typically formed on ananterior end of the device which will be held near the patient's lips inthe oral cavity while the vacuums 27 are on the posterior end of thedevice which will be near the patient's soft palate when the device isin the patient's oral cavity.

A vacuum is drawn in the plenum 22 by vacuum pump 28 which is connectedto the outlet 26 by tubular connector 20. To maintain a controlledvacuum in the plenum 22, an air source 30 is placed in front of theinlet 24, typically being connected by tubular connector 18. The vacuumpump 28 will typically be a diaphragm or other positive displacementpump where the pump speed may be varied in order to control the volumeand/or pressure of air pulled from the device 12. In order to controlthe pressure, the delivery capacity of the air source 30 may be selectedand/or controlled. Typically, the air source 30 will comprise a flowrestrictor having a fixed orifice, more usually having an orifice areain the range from 0.01 mm² to 0.025 mm². Optionally, however, the airsource 30 could comprise an adjustable orifice valve or a pump which isoperated to deliver a fixed volume of air bleed into the plenum 22. Insuch cases, the controller could automatically control either the valveor the positive pressure pump to help maintain the target vacuum withinthe plenum of the oral device.

A saliva or moisture trap 32 will be placed in the flow path from theoutlet 26 of the oral device 12 to the vacuum pump 28 in order toreceive most or all of the air flow from the oral device and to removesaliva and moisture from the air flow before entering the vacuum pump.Usually, the trap 32 will be placed close to the inlet to the vacuumpump although it could be elsewhere in the system.

Usually, at least one pressure and/or flow sensor 40 will be provided inthe air bleed inlet flow path between the air source 30 and the inlet24, or optionally though less desirably within the plenum 22 of thedevice itself. The pressure/flow sensor 40 will detect the pressure/flowwithin the plenum either directly or indirectly, allowing controller 34to control either the vacuum pump 28 and/or the air source 30 in orderto maintain a target vacuum within the plenum, typically in the rangefrom 20 mmHg to 75 mmHg, preferably in the range from 30 mmHg to 55mmHg.

Optionally, a second pressure and/or flow sensor 42 may be providedbetween the outlet 26 of the oral device 12 and the vacuum pump 28,typically between the saliva trap 32 and the vacuum pump 28. Thepressure and/or flow measured by sensor 42 can be compared with thereading from sensor 40 to make sure that the flow and/or pressure withinthe plenum 22 of the oral device 12 are within proper operating ranges.For example, should saliva or any other material or failure block flowwithin the plenum 22, the readings between the sensor 40 and sensor 42would be expected to deviate substantially, indicating a system failure.

Referring now to FIGS. 3 and 4, an exemplary oral device 50 isillustrated. The oral device is fabricated from a polymer such as apolycarbonate or a polyvinyl acetate polymer (e.g., Versaflex® polymer),which may be molded or otherwise formed to have an anterior end 52 and across-member 54 at a posterior end. Bite plates 56 are formed on eachside of the oral device 50, and the cross-member 54 includes a pluralityof vacuum ports 58 formed on an upwardly and forwardly inclined surface60 of the cross-member 54. Plenum 62 is formed in the interior of theoral device 50 and provides a circulation path shown by the arrows inFIG. 4. While the oral device 50 is exemplary of those useful in thesystems and methods of the present invention, many other devices havingthe vacuum plenum, inlet and outlet, and vacuum ports would also beuseful.

Referring to FIG. 5, an oral appliance 70 constructed in accordance withan alternative aspect of the present invention comprises a first bitestructure or leg 74 and a second bite structure or leg 76. The first andsecond bite structures are joined at a posterior end by a cross-member79 having a plurality of vacuum ports 84 formed over a posterior surfacethereof. An air bleed, as generally described above, enters an interiorpassage or a lumen within the first bite structure 74 through an inlet78. Instead of circulating through a continuous plenum to outlet 80, aswith previous embodiments, the air entering through inlet 78 will passinto the patient's oral cavity through a bypass outlet 82. That air, orat least an equivalent volume or mass of air, will pass back into theplenum through the vacuum ports 84 together with any additional airwhich may have leaked into the patient's oral cavity which needs to beremoved. The combined air streams will then flow down through the secondbite structure or leg 76 and out the outlet 80, to the vacuum controlsystem as described previously for other embodiments. In order toisolate the higher pressure region of the plenum in the first leg 74from the lower pressure region of the plenum in the second leg 76, abarrier 86 will usually be disposed in the plenum between the bypassport 80 and the vacuum ports 84.

Referring now to FIG. 6, an oral appliance 90 incorporating stillalternative features of the present invention includes a first bitestructure or leg 92 and a second bite structure or leg 94. The firstbite structure 92 has an interior passage or lumen which is divided intoinlet and outlet segments by a barrier or wall 100. A plenum inlet 98 islocated at the anterior end of a first of the divided passages so thatair bleed entering the inlet can flow in a posterior direction until itreaches cross-member 95 disposed between the bite structures 92 and 94.A wall or partition 100 terminates at that point so the air inflow canturn to pass in the opposite direction through the second portion of thedivided air plenum so that a continuous air bleed is constantlymaintained by vacuum port(s) 102 located on a posterior surface of thecross-member. The combined flows of the air bleed and any air which isdrawn in through the vacuum port(s) then extends in an anteriordirection through the other segment of the passage within the first bitestructure so that it can exit through outlet 96. Usually, but notnecessarily, the interior of the second bite structure or leg 94 will beblocked and isolated from the air flow so that it does not becomecontaminated.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, substitutions,and equivalents may be used. Therefore, the above description should notbe taken as limiting the scope of the invention, which is defined by theappended claims.

What is claimed is:
 1. An oral device comprising: a base adapted to beheld between a patient's upper teeth and lower teeth, said base havingan anterior end, a posterior end, and a cross-member extending acrosssaid posterior end; wherein a plenum extends within the base from an airinlet on the anterior end to the cross-member and returns to an airoutlet on the anterior end, wherein the air inlet part and air outletare fluidly connected by the plenum so that air entering the inlet flowsthrough the cross-member before exiting the outlet; and wherein at leastone vacuum port is formed in a wall of the cross-member.
 2. A device asin claim 1, wherein the base includes left and right bite structures andthe cross-member is disposed between said bite structures.
 3. A deviceas in claim 1, wherein the plenum extends continuously through one bitestructure, across the cross-member, and through the other bite structureso that a controlled air flow is maintained from the inlet to theoutlet.
 4. A device as in claim 1, wherein the plenum extends from theinlet to a bypass outlet and a barrier is disposed between the bypassoutlet and the vacuum ports.
 5. A device as in claim 1, wherein theplenum in one bite structure is divided into inlet and outlet lumensconnected to the inlet and outlet, respectively.
 6. A device as in claim1, wherein the cross-member is spaced inferiorly of the hard palate whenthe base is held between the patient's teeth, wherein a clear regionfree from structure is defined between the cross-member and the hardpalate and extending to the patient's soft palate.
 7. A device as inclaim 1, wherein the at least one vacuum port is disposed on a superiorsurface of the cross-member.
 8. A device as in claim 1, furthercomprising a lip seal coupled to the base and/or the vacuum conduit toinhibit air from entering the oral cavity through the mouth.
 9. A deviceas in claim 1, wherein the cross-member comprises an arcuate rear edgeand a curved superior surface.